JPH07199683A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device which forms a highly accurate, high quality image and to simplify the structure of the device. CONSTITUTION:A photosensitive belt 2 forms a closed loop by being stretched between a roller group consisting of three rollers: a large-diameter roller 10, a separation roller 12, and a tension roller 21. The belt runs counterclockwise, in the direction shown by the arrow P, having the large-diameter roller 10 as a drive roller. Further, a transfer mechanism is composed of the large- diameter roller 10 and a pressure roller 14, and the photosensitive belt 2 and a transfer sheet 15 are superimposed between the large-diameter roller 10 and the pressure roller 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, and more particularly to improvement of an image forming apparatus using a photosensitive belt.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic process (so-called Carlson process) has been widely adopted as a method for image formation in various printers, copying machines and the like. This electrophotographic process forms an image on recording paper through an image forming process such as charging, exposure, development (dry development or wet development), transfer, and fixing. For example, according to the wet development method, silver salt photography is used. It is possible to obtain resolution and gradation comparable to

By the way, in the image forming apparatus for forming an image by the above-mentioned electrophotographic process, in order to continuously perform a series of image forming processes, a drum system in which the photoconductor is drum-shaped and a belt in which the photoconductor is belt-shaped are used. The type is known.

The former uses, as a photosensitive member, an aluminum drum having an Se-based photosensitive material (for example, Se-Te) vapor-deposited on its surface, an aluminum drum coated with an organic photoconductor, and the like. The photosensitive drum is driven to rotate. Then, steps such as charging, exposure, development, and transfer are performed. On the other hand, the latter uses a belt made of an organic photoconductor or the like, and performs the same steps on a photosensitive belt run by rollers.

[0005]

However, these drum-type and belt-type image forming apparatuses have respective advantages and disadvantages, and their improvement is awaited.

For example, in the drum type, the shape and size of the photosensitive drum are required to be highly accurate, the manufacturing cost thereof is very high, and the apparatus becomes expensive.

On the other hand, the belt system is advantageous in terms of manufacturing cost, but it is a system in which the photosensitive belt is stretched and driven by rollers, so that the running state of the belt is stable. difficult. For example, depending on the position of the driving roller, the photosensitive belt may be loosened, or the cleaning blade may become a load to make the running state unstable, which may cause a significant deterioration in image quality.

Further, the applicant of the present application has previously mentioned that Japanese Patent Laid-Open No. 2-6
In 966 and Japanese Patent Laid-Open No. 2-6967,
We have proposed a wet development method using a solidified developer, but when applying such a development method to the above belt type image forming apparatus, it is necessary to dispose a backing plate with a built-in heater in the developing section or to perform cleaning. It is necessary to add a heating roller near the blade, which makes the structure very complicated.

Therefore, the present invention has been proposed in order to solve the drawbacks of the conventional image forming apparatus, and an object thereof is to provide an image forming apparatus capable of high-definition and high-quality image formation. Further, it is an object of the present invention to provide an inexpensive image forming apparatus that can simplify the apparatus configuration.

[0010]

In order to achieve the above-mentioned object, an image forming apparatus of the present invention comprises a photosensitive belt, a roller group including a large-diameter roller and forming a traveling path of the photosensitive belt, An image forming process section having at least a charging section, an exposing section and a developing section is provided, and the image forming process section is arranged in the vicinity of the large diameter roller and formed on the photoreceptor belt on the large diameter roller. The developed developer image and the transferred material are superposed.

The present invention further comprises a photoconductor belt, a group of rollers including a large-diameter roller which constitutes a traveling path of the photoconductor belt, and an image forming process section having at least a charging section, an exposing section and a developing section. The image forming process section is arranged in the vicinity of the large-diameter roller, and the transferred body to which the developer image has been transferred and the photosensitive belt are separated on the large-diameter roller.

At this time, the large-diameter roller is configured as a driving roller for running the photosensitive belt.

The large diameter roller may be made of aluminum and a heating means may be provided therein.

Further, the roller group is composed of two rollers including a large-diameter roller, and a peeling roller for peeling the developer image formed on the superposed photoreceptor belts and the transferred material is the photoreceptor. It may be configured as one roller which also serves as a tension roller for adjusting the tension applied to the belt.

The roller group includes a large-diameter roller 2
The contact roller is composed of two rollers, and the contact roller for superposing the developer image formed on the photosensitive belt and the transferred material is constituted as one roller which also serves as a tension roller for adjusting the tension applied to the photosensitive belt. May be.

That is, the image forming apparatus of the present invention basically adopts a belt system, but the steps of charging, exposing, developing and the like run along the peripheral surface of the large diameter roller. By doing so, the image formation is stabilized and the image quality equal to or higher than that of the drum system is secured.

Therefore, the large-diameter roller needs to have a size enough to dispose at least the charging section, the exposing section, and the developing section on the periphery, and specifically, the diameter needs to be 50 mm or more. In this case, it is not necessary to increase the diameter of the large-diameter roller more than necessary, but in order to secure sufficient torque and smoothly feed the photosensitive belt when the large-diameter roller is used as the driving roller, the diameter of the large-diameter roller is 100 mm. It is preferable to set the degree.

On the other hand, the remaining rollers are meaningless if they are made too large, and rather the size of the device is increased. Therefore, the diameter of the remaining rollers is made smaller than that of the large rollers. Therefore, the diameter of this small diameter roller is preferably 50 mm or less.
It is desirable to set it to about 0 mm.

In the image forming apparatus of the present invention, one of the rollers forming the roller group is a tension roller, and a predetermined tension is applied to the photosensitive belt stretched between these roller groups. If so, the stretched state becomes stable and the image quality is further improved.

In the image forming apparatus of the present invention, as the developing method, either a dry developing method or a wet developing method can be adopted, and further, the wet developing method using the solidified developer described above is also applicable.

The image forming process in the image forming apparatus of the present invention may be a single color (so-called monochrome) image forming process or a color image forming process for forming a color image. In the latter case, for example, a developing unit for developing with magenta, cyan, and yellow developers may be arranged around the large-diameter roller.

[0022]

Since the image forming apparatus of the present invention is basically of the belt type, it has the advantage of the belt type. That is,
It can easily cope with large-sized images and can reduce the manufacturing cost compared to the drum system.

Further, since the image forming apparatus of the present invention performs the steps of charging, exposing, developing and the like on the photosensitive belt running along the peripheral surface of the large diameter roller, the advantage of the drum system is obtained. In addition, the running state of the photoconductor belt becomes stable, and high definition and high quality images can be achieved. Moreover, since the developer image formed on the photosensitive belt and the transfer target are superposed on the large-diameter roller, the contact roller for performing the superposing operation is the roller. It is omitted from the group, and the device configuration is simplified.

Further, since the image forming apparatus of the present invention performs the steps of charging, exposing, developing and the like on the photosensitive belt running along the peripheral surface of the large diameter roller, it has the advantage of the drum system. In addition, the running state of the photoconductor belt becomes stable, and high definition and high quality images can be achieved. Moreover, since the developer image formed on the superposed photoreceptor belt and the transfer-receiving member are separated on the large-diameter roller, the separation roller for performing the separation operation is performed. Are omitted from the roller group, and the device configuration is simplified.

Further, in the roller group, the large diameter roller is a driving roller for traveling the photosensitive belt, and the remaining small diameter rollers are driven rollers, whereby the traveling state of the photosensitive belt is most stable. , The imaging process is stabilized.

Since the large-diameter roller is made of aluminum and the heating means is provided inside, it is not necessary to additionally add a backing plate, a heating roller and the like, so that the apparatus can be simplified and the development can be performed efficiently. The part is heated to a predetermined temperature to melt the solidified developer.

Further, in the present invention, the peeling roller, in which the roller group is composed of two rollers including the large-diameter roller, peels the developer image formed on the superposed photosensitive belts from the transferred material. Since it also functions as a tension roller that adjusts the tension applied to the photosensitive belt,
The device configuration is further simplified.

Further, in the present invention, the roller group is composed of two rollers including a large-diameter roller, which guides the traveling of the photoconductor belt and at the same time the developer image formed on the photoconductor belt and the transferred material. The overlapping contact roller also serves as a tension roller for adjusting the tension applied to the photosensitive belt, so that the apparatus configuration is further simplified.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some specific embodiments to which the present invention is applied will be described below in detail with reference to the drawings.

First, the first embodiment will be described. Figure 1
FIG. 1 shows a monochrome laser printer device 1 to which the present invention is applied, which is an image forming device according to the first embodiment. The printer device 1 includes a photoconductor belt 2, a charging charger (charging unit) 3,
An image forming process unit including a laser optical system (exposure unit) 4, a developing device (developing unit) 5, a charge eliminating lamp 6, a cleaning mechanism including a cleaning blade 7, and a transfer mechanism unit are incorporated.

A single or a plurality of paper feed cassettes 8, two paper feed cassettes (not shown) having different paper sizes in this example, are detachably loaded in the printer body and set in each paper feed cassette. A developer image is formed on the transferred transfer sheet.

Here, the material that can be used as the transfer sheet is preferably one having a large adhesive force to the developer, and can be appropriately selected according to the application. For example, various kinds of paper such as natural paper and synthetic paper, cloth or non-woven fabric composed of vegetable fibers such as cotton and hemp, and animal fibers such as silk and wool, organic synthetic fibers such as polyamide, polyester, polyacetal and polyurethane. Or a cloth or non-woven fabric made of inorganic fibers such as ceramics or carbon, a mesh of metal or organic polymer, or a polymer foam such as polyurethane foam. In order to save in the form of an ordinary document, it is preferable to use a white background paper or the like as the transfer target from the viewpoint of enhancing the visibility, but it is not limited to this.

The transfer sheet may have a resin layer compatible with the dispersion medium of the developer formed on the surface thereof in order to secure the adhesive force to the developer. Thereby, the transfer of the developer image can be made more reliable.

The resin forming the resin layer formed on the surface of the transfer sheet may be any resin as long as it is compatible with the dispersion medium, for example, thermoplastic elastomer, low density polyolefin, ionomer resin, Vinyl acetate copolymer polyolefin, low molecular weight polyolefin,
A hot melt adhesive or the like can be used. These are commercially available under the trade name Chemipearl (A type, M type, S type, V type, W type) (all manufactured by Mitsui Petrochemical Co., Ltd.) and the trade name Acryft (manufactured by Sumitomo Chemical Co., Ltd.). In this example, a sheet coated with vinyl acetate copolymer polyolefin (Vicat softening point: 40 ° C.) was used.

On the other hand, the photosensitive belt 2 is formed by molding a negatively charged phthalocyanine-based organic photosensitive material into a belt shape. In addition to the phthalocyanine-based organic photosensitive material, well-known organic photoconductors are used. Can be used. Specifically, poly-N-vinylcarbazole and 2,
Electrophotographic photosensitive base material composed of 4,7-trinitrofluoren-9-one, poly-N-vinylcarbazole sensitized with pyrylium salt dye, and poly-N-vinylcarbazole sensitized with cyanine dye. Examples thereof include an electrophotographic photosensitive substrate containing an organic pigment as a main component, an electrophotographic photosensitive substrate containing a eutectic complex composed of a dye and a resin as a main component, and the like.

The photosensitive belt 2 is wound around a plurality of rollers, in this example, a roller group consisting of three rollers, a large diameter roller 10, a peeling roller 12 and a tension roller 21, to form a closed loop. Large diameter roller 10
As a driving roller, the large-diameter roller 10 is driven in the counterclockwise direction indicated by the arrow M in the figure, so that the large-diameter roller 10 travels in the counterclockwise direction indicated by the arrow P in the figure.

Here, the large-diameter roller 10 has a larger diameter than the other rollers, and has a diameter of 100 mm in this example. On the other hand, the peeling roller 12 and the tension roller 21
Is composed of a small-diameter roller having a diameter of about 30 mm. Further, in this example, the tension roller 21 is provided between the peeling roller 12 and the large-diameter roller 10 and applies a constant tension to the photoconductor belt 2 so that the photoconductor belt 2
I try to drive the car stably.

In the traveling system having the above-described structure, the photosensitive belt 2 travels along the peripheral surface of the large-diameter roller 10 and then passes through the peeling roller 12 and the tension roller 21 and again the large-diameter roller 10. Drive over When traveling along the peripheral surface of the large-diameter roller 10, the back side of the photosensitive belt 2 is supported by the large-diameter roller 10, so that the photosensitive belt 2 is loosened,
There is no risk of unstable driving.

Therefore, in this embodiment, the image forming process section and the cleaning mechanism are arranged along the peripheral surface of the large-diameter roller 10, and the photosensitive belt that runs along the peripheral surface of the large-diameter roller 10 is arranged. The image forming process is performed for 2. That is, the static elimination lamp 6, the cleaning blade 7, the charging charger 3, the laser optical system 4, and the developing device 5 are arranged so as to surround the large diameter roller 10.
A series of image forming processes (static elimination → cleaning → charging → exposure → development → ...) Is continuously performed. Therefore, the stability of the imaging process is comparable to the drum system. Regarding the static elimination lamp 6,
It is not always necessary to arrange around the large diameter roller 10,
It is also possible to install it at an arbitrary position between the peeling roller 12 and the large diameter roller 10.

The charging charger 3, the laser optical system 4, and the developing device 5 which compose the image forming process section may be of the ordinary electrophotographic type, and the type is not limited, but in this example, the charging is performed. A scorotron was used as the charger 3. This charging charger (scorotron) 3
The discharge wire 31 and the mesh 32 provided on the opening surface and functioning as a grid electrode enable uniform charging without unevenness.

The laser optical system 4 is composed of a laser light source 41, a polygon mirror (not shown) for scanning the laser beam on the photosensitive belt 2, a reflection mirror 42, etc. Depending on the photoconductor belt 2
Selective exposure.

The developing device 5 may be of a dry type or a wet type, but in this example, it is melted by heating or cooling,
The developing device uses a solidified wet developer that is repeatedly solidified. That is, the developing device 5 includes a developer container 51 containing a solidified developer, a developing roller 52, and a squeeze roller 53 described later, and the molten solidified wet developer in the developer container 51 is It is supplied to the surface of the developing roller 52 that rotates at a constant speed in the clockwise direction indicated by the middle arrow N, and is used for developing the electrostatic latent image on the surface of the photosensitive belt 2.

Here, after the completion of the developing process, excess developer (mainly the carrier liquid which is a solvent) may stay on the photosensitive belt 2 and adversely affect the subsequent transferring process.
Therefore, in order to prevent this, the squeeze roller 53, which is a squeeze member that is in contact with the photoconductor belt 2, is provided between the developing roller 52 and a pressure roller 14 described later as an excess developer removing mechanism section. Has been.

The squeeze roller 53 on the belt-shaped photosensitive member 1
No backing member is provided at the position where the squeeze roller 53 is provided, and the squeeze roller 53 is brought into contact with the belt-shaped photoconductor 1 with a slight pressure by the elastic force of the photoconductor belt 2. In this case, microscopically, since the developer intervenes between the surface of the photosensitive belt 2 and the surface of the squeeze roller 53, the developed toner on the surface of the photosensitive belt 2 is scratched. The excess developer can be removed by rotating the squeeze roller 53 in the counterclockwise direction indicated by arrow L at a constant speed without dropping it.

The dispersion medium used in the solidified wet developer is an electrically insulating organic substance, and its melting point is set to 30 ° C. or higher, more preferably 40 ° C. or higher in consideration of the normal use environment and handleability. . Although the upper limit of the melting point is not particularly specified, it is practically about 100 ° C., more preferably 80 ° C. or lower. This is because even if the melting point is too high, extra energy is consumed for heating, and when it is used by holding it on a support, it must not exceed the heat resistant temperature of the material generally used as a support. In consideration. In this example, the melting point of the developer is set to 46 ° C.

Examples of materials for the dispersion medium which satisfy these requirements include paraffins, waxes, and mixtures thereof. First, as paraffins, various normal paraffins having 19 to 60 carbon atoms from nonadecane to hexacontane are available. As waxes, carnauba wax,
Examples thereof include vegetable waxes such as cotton wax, animal waxes such as beeswax, ozokerite, and petroleum waxes such as paraffin wax, microcrystalline wax, petrolatum and the like. These materials are generally dielectric materials having a dielectric constant ε of about 1.9 to 2.3. In addition, an ethylene vinyl acetate copolymer or the like may be added in order to increase the cohesive force of the dispersion medium.

Furthermore, polyethylene, polyacrylamide, poly-n-stearyl acrylate, poly-n
-A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or a copolymer of polyacrylate such as stearyl methacrylate (for example, copoly-n-stearyl acrylate-ethyl methacrylate) can be used, but the viscosity upon heating Considering the above, the above paraffins and waxes are preferable.

As the colorant particles dispersed in the electrically insulating organic material, conventionally known inorganic pigments, organic pigments,
Dyes and mixtures of these can be used. Examples of the inorganic pigment include chrome-based pigments, cadmium-based pigments, iron-based pigments, cobalt-based pigments, ultramarine blue and navy blue. As an organic pigment or dye, Hansa Yellow (CI11
680), Benzidine Yellow G (CI21090), Benzidine Orange (CI21110), Fast Red (CI3708)
5), Brilliant Carmine 3B (CI16015-Lake), Phthalocyanine Blue (CI74160), Victoria Blue
(CI42595-Lake), Spirit Black (CI50415)
, Oil blue (CI74350), alkali blue (CI4
2770A), First Scarlet (CI12315), Rhodamine 6B (CI45160), Rhodamine Rake (CI4516)
0-Lake), Fast Sky Blue (CI74200-Lake)
Nigrosine (CI50415), carbon black and the like. These may be used alone or as a mixture of two or more kinds, and those having a desired color development may be selected and used.

In addition to the electrically insulating organic substance and the colorant particles, a resin may be used in combination with the developer for the purpose of improving the dispersibility and the chargeability of the colorant. As such a resin, known materials can be appropriately selected and used. For example, rubbers such as butadiene rubber, styrene-butadiene rubber, cyclized rubber, natural rubber, styrene resin, vinyltoluene resin, acrylic resin can be used. -Based resins, methacrylic-based resins, polyester-based resins, polycarbonate-based resins, polyvinyl acetate-based resins and other synthetic resins, rosin-based resins, hydrogenated rosin-based resins, alkyd resins including modified alkyds such as linseed oil-modified alkyd resins , Natural resins such as polyterpenes, and the like. In addition, modified phenol resins such as phenol resins and phenol formalin resins, pentaerythritol phthalate, coumarone-indene resins, ester gum resins and vegetable oil polyamide resins are also useful, and polyvinyl chloride and chlorinated Halogenated hydrocarbon polymers such as polypropylene, synthetic rubbers such as vinyltoluene-butadiene, butadiene-isoprene, 2
-Polymers of acrylic monomers having a long chain alkyl group such as ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, lauryl acrylate, octyl acrylate or copolymers thereof with other polymerizable monomers (for example, styrene-lauryl methacrylate) Copolymers, acrylic acid-lauryl methacrylate copolymers, etc.), polyolefins such as polyethylene, and polyterpenes can also be used.

Further, a charge-donating agent is usually added to the above-mentioned developer, and the developer used here is no exception. Examples of the charge donor used include metal salts of fatty acids such as naphthenic acid, octenoic acid, oleic acid, stearic acid, isostearic acid and lauric acid, metal salts of sulfosuccinic acid esters, oil-soluble sulfonic acid metal salts and phosphoric acid. Ester metal salts, metal salts such as abietic acid, aromatic carboxylic acid metal salts, aromatic sulfonic acid metal salts and the like.

In order to improve the charge of the colorant particles (6), SiO ₂ , Al ₂ O ₃ , TiO ₂ , Zn
O, Ga ₂ O _3, In ₂ O ₃ , GeO ₂ , SnO ₂ , P
Fine particles of metal oxide such as bO ₂ and MgO, or a mixture thereof may be added as a charge enhancer.

In the developing method using such a solidified wet type developer, it is necessary to heat the photosensitive belt 2 in order to melt the developer in the developing process and the cleaning process. For this reason, in this embodiment, the large-diameter roller 10 is made of aluminum having good thermal conductivity, and a heating means (for example, a resistor) 13 is provided inside to transfer the heat to the photosensitive belt 2. There is.

On the other hand, the transfer mechanism is composed of the large-diameter roller 10 and the pressure roller 14 described above.
0 and the pressure roller 14 and the photosensitive belt 2 and the transfer sheet 1
5 is sandwiched between the two. Here, the large-diameter roller 10 also serves as a guide roller for the photosensitive belt 2, and the pressure roller 14 serves as the transfer sheet 15.
Plays a role of overlapping the developed photosensitive belt 2. However, if the transfer sheet 15 itself is sufficiently pressed, the pressure roller 14 may be omitted.

Further, the transfer sheet 15 is transferred from the photosensitive belt 2.
A peeling roller 12 is provided at a position where the peeling roller 1 comes in contact with the back surface side of the photosensitive belt 2.
2 functions as a guide roller, and the traveling direction of the photosensitive belt 2 is changed. A cooling plate 16 is provided immediately in front of the peeling roller 12 so as to come into contact with the back surface side of the photoconductor belt 2.
Alternatively, the transfer sheet 15 is configured to be heated or cooled.

A fixing device 17 and a discharge unit 18 are arranged in the advancing direction of the peeled transfer sheet 15 so that the transfer sheet 15 can be smoothly discharged. The fixing device 17 provided in front of the discharging unit 18 is composed of a heat roller, a heat oven, or the like, and heats the transfer sheet 15 after transfer to a predetermined temperature (for example, 60 ° C.) to form a developer image. It is structured so that it can be fixed.

In this embodiment, the transfer sheet 15 is conveyed in a substantially horizontal direction from the pressure contact with the photosensitive belt 2 to the peeling. The transfer sheets 15 can be arranged in a straight line, and the transfer sheet 15 can be stabilized in a conveyed state. Although the transfer path of the transfer sheet 15 is set to the horizontal direction here, it goes without saying that the transfer path can be set in any direction depending on the configuration of the apparatus.

In the printer device described above, an electrostatic latent image is formed on the photosensitive belt 2 and is developed using a solidified wet type developer. That is, the photosensitive belt 2 is rotationally driven in the counterclockwise direction in the figure, the surface is charged by the charging charger 3, and then laser light from the laser optical system 4 is irradiated to form an electrostatic latent image. This electrostatic latent image is visualized by the developer when passing through the developing device 5.

On the other hand, the transfer sheet 15 is fed from the paper feeding cassette 8 through the registration roller 19 and is conveyed to the latent image carrier composed of the photosensitive belt 2 at a timing. Then, the visible image formed of the developer is transferred from the photosensitive belt 2 to the transfer sheet 15, and the transfer sheet 15 that is in close contact with the photosensitive belt 2 is mechanically separated.

For the transfer, the photosensitive belt 2 is run while holding the developed image, and the pressing roller 11 makes close contact with the transfer sheet 15 at the same timing, and pressurizes and heats (pressure contact heating: temperature 48 ° C.). By doing. As described above, the transfer mechanism is configured to sandwich the photosensitive belt 2 between the pressure roller 14 and the large-diameter roller 10,
The developer image is melted or softened by the pressurization of the pressure roller 14 and the large-diameter roller 10 and the heating by the heating means 13 inside the large-diameter roller 10, and the transfer onto the transfer sheet 15 is performed.

After pressure contact by the transfer mechanism, the photosensitive belt 2 and the transfer sheet 15 are conveyed in a close contact state and separated by the curvature separation on the separating roller 12. At the time of peeling, the peeling roller 12 may be heated and the photosensitive belt 2 may be slightly heated from the back side so that the visible image is easily peeled from the photosensitive belt 2. In this example, the peeling temperature was 30 ° C.

Thereafter, the transfer sheet 15 is fixed to the fixing device 17
The visible image on the transfer sheet 15 is fixed by the fixing device 17 and is discharged to the discharge portion 18.

On the other hand, the photosensitive belt 2 after the visible image transfer is
The static elimination lamp 6 removes the charged electric charge, and the cleaning blade 7 removes the residual developer, so that the developer is repeatedly used. The cleaning blade 7
When the residual developer is removed by the method, the photoconductor belt 2 is heated by the large-diameter roller 10 and the residual developer is melted.
Will be quickly removed by.

In the case of a color printer, instead of the image forming process unit in the apparatus shown in FIG. 1, yellow (Y), magenta (M), cyan (C) and, if necessary, black (K). Each color developing unit may be arranged around the large-diameter roller 10. In the case of a color printer, there are a method in which Y, M, C, and K colors are superposed on a photoconductor and are collectively transferred, and a method in which Y, M, C, and K images are transferred every time and colors are superposed on recording paper. Yes, either one may be adopted.

Since the image forming apparatus according to the first embodiment is basically of the belt type, it has the advantage of the belt type. That is, it is possible to easily cope with a large image, and the manufacturing cost is reduced as compared with the drum system.

The image forming apparatus of the first embodiment is
Since the steps of charging, exposing, developing, etc. are performed on the photoconductor belt 2 running along the peripheral surface of the large-diameter roller 10, it also has the advantage of the drum system and the running state of the photoconductor belt 2 Is stable, and high definition and high quality images can be achieved. Moreover, since the developer image formed on the photosensitive belt 2 and the transfer sheet 15 which is the transfer target are superposed on the large-diameter roller 10, the superposing operation is performed. The contact roller is omitted from the roller group, and the device configuration is simplified.

In the roller group, the large-diameter roller 10 is a driving roller for traveling the photosensitive belt 2, and the remaining small-diameter rollers are driven rollers, so that the traveling state of the photosensitive belt 2 is the most stable. And stabilize the imaging process.

Further, since the large-diameter roller 10 is made of aluminum and the heating means is provided inside, it is not necessary to additionally add a backing plate, a heating roller, etc., and the apparatus can be simplified. The developing section 5 is efficiently heated to a predetermined temperature and the solidified developer is melted.

As described above, in the first embodiment, similarly to the first embodiment, it is possible to always obtain a high quality image of the same quality with a relatively simple structure.

Here, a modified example of the image forming apparatus according to the first embodiment will be described. The same reference numerals are given to those corresponding to the members shown in the first embodiment.

This modification has substantially the same structure as the monochrome laser printer to which the image forming apparatus according to the first embodiment is applied, but as shown in FIG. 2, the tension roller 21 is omitted and the peeling roller is omitted. 12 is different in that it also serves as the tension roller.

That is, in the modification of the first embodiment, the photosensitive belt 2 is stretched between a plurality of rollers and between a roller group consisting of two rollers, a large diameter roller 10 and a peeling roller 12. A closed loop is formed, and the large-diameter roller 10 is used as a driving roller to travel counterclockwise in the drawing.

In the traveling system having the above-described structure, the photosensitive belt 2 travels along the peripheral surface of the large-diameter roller 10 and then passes through the peeling roller 12 and again the large-diameter roller 1.
Drive over 0. When traveling along the peripheral surface of the large-diameter roller 10, the back side of the photosensitive belt 2 is supported by the large-diameter roller 10, so that the photosensitive belt 2 is loosened, There is no risk of unstable driving.

Since the modified example of the image forming apparatus according to the first embodiment is basically of the belt type, it has the advantage of the belt type. That is, it is possible to easily cope with a large image, and the manufacturing cost is reduced as compared with the drum system.

The image forming apparatus according to the above modification is
Since the steps of charging, exposing, developing, etc. are performed on the photoconductor belt 2 running along the peripheral surface of the large-diameter roller 10, it also has the advantage of the drum system and the running state of the photoconductor belt 2 Is stable, and high definition and high quality images can be achieved. Moreover, since the developer image formed on the photosensitive belt 2 and the transfer sheet 15 which is the transfer target are superposed on the large-diameter roller 10, the superposing operation is performed. The contact roller is omitted from the roller group, and the device configuration is simplified.

In the roller group, the large diameter roller 10 is a driving roller for traveling the photosensitive belt 2, and the remaining small diameter rollers are driven rollers, so that the traveling state of the photosensitive belt 2 is the most stable. And stabilize the imaging process.

Furthermore, since the large-diameter roller 10 is made of aluminum and the heating means is provided inside, it is not necessary to add a backing plate, a heating roller, etc., and the apparatus can be simplified. The developing section 5 is efficiently heated to a predetermined temperature and the solidified developer is melted.

Further, in the above modification, the roller group is composed of two rollers including the large diameter roller 10, and the developer image formed on the superposed photosensitive belt 2 and the transfer sheet 15 are separated from each other. Since the peeling roller 12 also serves as the tension roller 21 that adjusts the tension applied to the photosensitive belt 2, the device configuration is further simplified.

As described above, in the modification of the first embodiment, similar to the above embodiment, it is possible to obtain a high quality image of the same quality with a relatively simple structure.

Next, a second embodiment of the present invention will be described. The same reference numerals are given to those corresponding to the members shown in the first embodiment.

The second embodiment has substantially the same structure as the monochrome laser printer to which the image forming apparatus according to the first embodiment is applied, but as shown in FIG. 3, a contact roller 11 is provided. The point where the developer image formed on the photoconductor belt 2 and the transfer sheet 15 are sandwiched and superposed by the contact roller 11 and the pressure roller 14, and the peeling roller 12 is used The difference is that the roller 10 also serves as the peeling roller 12.

In the second embodiment, the photosensitive belt 2 is composed of a plurality of rollers, a contact roller 11, and a large diameter roller 1.
0 and a tension roller 22 are wound around a roller group consisting of three rollers to form a closed loop, and the large-diameter roller 10 is used as a driving roller to travel counterclockwise in the drawing.

Further, in the second embodiment, a tension roller 22 is provided between the large diameter roller 10 and the contact roller 11 for stably running the photosensitive belt 2 while applying a constant tension. ing.

In the traveling system having the above-described structure, the photosensitive belt 2 travels along the peripheral surface of the large diameter roller 10, then passes through the tension roller 22 and the contact roller 11, and again the large diameter roller. Drive over 10. When traveling along the peripheral surface of the large-diameter roller 10, the back side of the photosensitive belt 2 is supported by the large-diameter roller 10, so that the photosensitive belt 2 is loosened,
There is no risk of unstable driving.

On the other hand, the transfer mechanism comprises a pressure roller 14 and a contact roller 11, and the pressure roller 14 and the contact roller 11 sandwich the photosensitive belt 2 and the transfer sheet 15. ing. Of these rollers, the contact roller 11 also serves as a guide roller for the photoconductor belt 2, and the pressure roller 14 serves to superpose the transfer sheet 15 on the developed photoconductor belt 2. However, if the transfer sheet 15 itself is sufficiently pressed, the pressure roller 14 may be omitted.

Particularly, at the position where the transfer sheet 15 is peeled from the photosensitive belt 2, the large diameter roller 10 is provided so as to contact the back side of the photosensitive belt 2, and the large diameter roller 10 is a guide roller. And the traveling direction of the photosensitive belt 2 is changed. That is, in the second embodiment, the large diameter roller 10 also serves as the peeling roller 12. At the position of the large diameter roller 10 immediately before this,
A cooling plate 16 is provided so as to be in contact with the back surface side of the photoconductor belt 2, and is configured to heat or cool the photoconductor belt 2 or the transfer sheet 15 as necessary.

Since the image forming apparatus according to the second embodiment is basically of the belt type as in the first embodiment, it has the advantage of the belt type. That is, it is possible to easily cope with a large image, and the manufacturing cost is reduced as compared with the drum system.

In the image forming apparatus according to the second embodiment, the steps of charging, exposing, developing, etc. are performed on the photosensitive belt 2 running along the peripheral surface of the large diameter roller 10. Therefore, it also has the advantages of the drum system, the running state of the photosensitive belt 2 becomes stable, and high definition and high quality of the image can be achieved. Moreover, this large diameter roller 10
Since the developer image formed on the photosensitive belt 2 and the transfer sheet 15 which are superposed on each other are peeled off from each other, the peeling roller 12 for performing this peeling operation is separated from the roller group. It is omitted, and the device configuration is simplified.

Further, in the above roller group, the large diameter roller 10 is used as a driving roller for traveling the photosensitive belt 2, and the remaining small diameter rollers are driven rollers, so that the traveling state of the photosensitive belt 2 is the most stable. And stabilize the imaging process.

Further, since the large-diameter roller 10 is made of aluminum and the heating means is provided inside, it is not necessary to additionally add a backing plate, a heating roller, etc., and the apparatus can be simplified. The developing section 5 is efficiently heated to a predetermined temperature and the solidified developer is melted.

As described above, in the second embodiment, as in the case of the above-described embodiment, it is possible to always obtain a high quality image of the same quality with a relatively simple structure.

Here, a modification of the image forming apparatus according to the second embodiment will be described. The same reference numerals are given to those corresponding to the members shown in the first embodiment.

This modification has substantially the same structure as the monochrome laser printer to which the image forming apparatus according to the second embodiment is applied, but the tension roller 22 is omitted as shown in FIG. The difference is that the roller 11 also serves as this tension roller.

That is, in the modified example of the second embodiment, the photosensitive belt 2 is stretched between a plurality of rollers and between a roller group consisting of two rollers, a large diameter roller 10 and a contact roller 11. To form a closed loop, and the large-diameter roller 10 is used as a driving roller to travel counterclockwise in the drawing.

In the traveling system having the above-described structure, the photosensitive belt 2 travels along the circumferential surface of the large diameter roller 10, then passes through the contact roller 11, and again the large diameter roller 1
Drive over 0. When traveling along the peripheral surface of the large-diameter roller 10, the back side of the photosensitive belt 2 is supported by the large-diameter roller 10, so that the photosensitive belt 2 is loosened, There is no risk of unstable driving.

The modified example of the image forming apparatus according to the second embodiment has the advantage of the belt system since it is basically of the belt system as in the first embodiment. That is, it is possible to easily cope with a large image, and the manufacturing cost is reduced as compared with the drum system.

The image forming apparatus according to the above modification is
Since the steps of charging, exposing, developing, etc. are performed on the photoconductor belt 2 running along the peripheral surface of the large-diameter roller 10, it also has the advantage of the drum system and the running state of the photoconductor belt 2 Is stable, and high definition and high quality images can be achieved. Moreover, since the developer image formed on the superposed photosensitive belt 2 and the transfer sheet 15 are peeled off on the large-diameter roller 10, this peeling operation is performed. The peeling roller 12 is omitted from the roller group, and the device configuration is simplified.

Further, in the above roller group, the large diameter roller 10 is used as a driving roller for traveling the photosensitive belt 2, and the remaining small diameter rollers are driven rollers, whereby the traveling state of the photosensitive belt 2 is the most stable. And stabilize the imaging process.

Further, since the large-diameter roller 10 is made of aluminum and the heating means is provided inside, it is not necessary to add a backing plate, a heating roller and the like separately, and the apparatus can be simplified. The developing section 5 is efficiently heated to a predetermined temperature and the solidified developer is melted.

Further, in the modified example of the second embodiment, the roller group is composed of two rollers including the large diameter roller 10, and is formed on the photosensitive belt 2 while guiding the traveling of the photosensitive belt 2. Developer image and transfer sheet 15
Since the contact roller 11 for superimposing and also serves as the tension roller 22 for adjusting the tension applied to the photoconductor belt, the structure of the apparatus is further simplified.

As described above, in the modified example of the second embodiment, it is possible to always obtain a high quality image of the same quality with a relatively simple structure as in the above embodiment.

Although some specific examples to which the present invention is applied have been described above, it goes without saying that the present invention is not limited to these examples.

[0102]

According to the present invention, a photosensitive belt, a group of rollers including a large-diameter roller and forming a traveling path of the photosensitive belt, and an image forming process section having at least a charging section, an exposing section and a developing section are provided. The image forming process section is arranged in the vicinity of the large diameter roller, and the developer image formed on the photosensitive belt and the transfer target are superposed on the large diameter roller. As a result, it is possible to easily deal with large images, simplify the device configuration,
It is possible to reduce the size of the device and reduce the manufacturing cost. Further, since the running state of the photoconductor belt can be made stable, it is possible to obtain an image of high definition and high quality comparable to the drum system.

Further, in the present invention, the photoconductor belt, a group of rollers including a large-diameter roller and forming a traveling path of the photoconductor belt, and an image forming process section having at least a charging section, an exposing section and a developing section are provided. The image forming process section is arranged in the vicinity of the large-diameter roller, and the transferred body to which the developer image is transferred and the photoconductor belt are separated on the large-diameter roller. Therefore, it is possible to easily cope with a large image, and it is possible to simplify the configuration of the device, reduce the size of the device, and reduce the manufacturing cost. Also, since the running state of the photoconductor belt can be made stable, high definition comparable to the drum system,
It is possible to obtain a high quality image.

In this case, since the large-diameter roller is configured as a driving roller for running the photosensitive belt, the running of the photosensitive belt is stabilized around the large-diameter roller, and the high-definition and high-quality comparable to the drum system is obtained. It is possible to obtain an image of.

Since the large-diameter roller is made of aluminum and the heating means is provided therein,
The solidified wet developer on the photosensitive belt can be stably and reliably melted, and the quality of the image can be improved.

Further, the roller group is composed of two rollers including a large-diameter roller, and a peeling roller for peeling the developer image formed on the superposed photoreceptor belts from the transferred body is the photoreceptor. Since the roller is configured as one roller that also serves as a tension roller that adjusts the tension applied to the belt, it is possible to further simplify the apparatus configuration, reduce the apparatus size, and reduce the manufacturing cost.

Further, the above roller group includes a large diameter roller 2
The contact roller is composed of two rollers, and the contact roller for superposing the developer image formed on the photosensitive belt and the transferred body is constituted as one roller which also serves as a tension roller for adjusting the tension applied to the photosensitive belt. Therefore, it is possible to realize further simplification of the device configuration and to reduce the device size and manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an image forming apparatus according to a first embodiment.

FIG. 2 is a schematic diagram showing a modification of the image forming apparatus according to the first embodiment.

FIG. 3 is a schematic diagram showing an image forming apparatus according to a second embodiment.

FIG. 4 is a schematic diagram showing a modification of the image forming apparatus according to the second embodiment.

[Explanation of symbols]

 2 ... Photosensitive belt 3 ... Charging charger (charging part) 4 ... Laser optical system (exposure part) 5 ... Developing device (developing part) 10 ... Large diameter roller 11 ... Contact roller 12 ... Peeling roller 14 ... Pressure roller 21, 22 ... Tension roller

Claims (6)

[Claims] 1. A photosensitive belt, a group of rollers including a large-diameter roller that constitutes a traveling path of the photosensitive belt, and an image forming process section having at least a charging section, an exposing section and a developing section. An image forming process in which an image forming process section is disposed in the vicinity of the large-diameter roller, and the developer image formed on the photoconductor belt is superposed on the transferred body on the large-diameter roller. apparatus. 2. A photosensitive belt, a roller group including a large-diameter roller to form a traveling path of the photosensitive belt, and an image forming process section having at least a charging section, an exposing section and a developing section. An image forming apparatus characterized in that an image forming process section is arranged in the vicinity of the large-diameter roller, and a transfer-receiving body on which a developer image has been transferred is separated from the photosensitive belt on the large-diameter roller. 3. The image forming apparatus according to claim 1, wherein the large-diameter roller is a driving roller for running the photosensitive belt. 4. The image forming apparatus according to claim 1, wherein the large diameter roller is made of aluminum and a heating means is provided inside. 5. A peeling roller for peeling a developer image formed on a superposed photosensitive belt from a transfer-receiving member is formed on the photosensitive belt by a roller group including two rollers including a large-diameter roller. The image forming apparatus according to claim 1, wherein the image forming apparatus is also used as a tension roller for adjusting the applied tension. 6. A roller group is composed of two rollers including a large-diameter roller, and an abutting roller for superimposing a developer image formed on the photosensitive belt and a transfer-receiving member applies tension to the photosensitive belt. The image forming apparatus according to claim 2, wherein the adjusting tension roller also serves as a tension roller.